Preslaughter practices, pork physicochemical attributes and fatty acid profiles of pigs raised and slaughtered on smallholder urban farms in the Cape Metropole, South Africa

Abstract

Pre-slaughter practices, pork physicochemical quality, and fatty acid (FA) composition of 36 Landrace barrows aged six months, sourced from five smallholder urban farms (SUFs) in low-income, high-density suburbs and one commercial abattoir in Cape Metropole District, South Africa were evaluated. Pigs on SUFs were fed three diets: (1) kitchen-bakery-vegetable waste-based, (2) bakery-dairy waste-based, or (3) homemade grain-based, while those on a large-scale farm were fed a commercial diet. Pigs on SUFs were either stunned mechanically or not stunned before slaughter. The SUFs either practiced throat or cervical spine sticking during slaughter. Carcasses from pigs fed the homemade grain-based diet had higher (P ≤0.05) weights, ash subcutaneous and intramuscular fat (IMF) values than those fed the other diets. The homemade grain-based diet, throat sticking treatment produced pork with the highest pH45 followed by the bakery-dairy waste-based diet, throat sticking and kitchen- bakery vegetable waste-based diet, cervical spine treatments (P ≤ 0.05). Pigs fed a commercial diet and slaughtered by throat sticking produced pork with the lower (P ≤0.05) values for pH24, colour coordinates (L*, a*, b*, H◦ and C◦) and the higher (P ≤0.05) carcass temperature and shear force values relative to the other treatments. Pork from pigs fed the homemade grain-based diets had higher (P ≤0.05) contents of total FA, total PUFA, individual and total n-6 PUFA than pork from pigs fed the other diets. Pig carcasses stunned with a gun had higher (P ≤0.05) pH45, pH24 and shear force values than those not stunned. The homemade grain-based diet improved carcass attributes and fatty acid profiles of pigs raised and slaughtered on SUFs, stunning enhanced pork physical quality attributes while the kitchen-bakery-vegetable waste based diet, cervical spine sticking treatment produced less desirable pork physical attributes.